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It would be nice if this was a shopping question - but it is 99%+ likely to be an electronic construction question :-(.

I wish to find the quickest / easiest / cheapest way to read a 4GB NAND Flash IC in a damaged USB memory stick. The onboard controller IC is dead.The Flash IC may also be dead but I will assume it isn't until it becomes otherwise obvious.

Reading it could involve

(1) Making a custom reader,

Maybe not a wholly silly idea as connections to Flash are fewish (8 data and a handful of controls.)

How likely it is that I could easily access the data if I did this I don't yet know. Obtaining a bit image is bearable worst case BUT I'd far far rather have something that "sees" the files system and files as was. Of course.

(2) soldering in a new controller IC

I do not yet know if these are in common use in other devices. Sample of 1 checked so far had 100% non-match. There may be an industry standard, part number irregardless, I know not (yet).

SK6211. QFP48. Outline description here and
Datasheet here.

enter image description here

Or

(3) Removing the Micron 29F32G08QAA 32 mbit NAND Flash IC.
Datasheet not yet located.

Markings VERY dim. Here is "enhanced photo image of markings".

enter image description here

SO

Does anyone have any suggestions how I might BEST read this memory with original format, or at all?

Any thoughts on source of 6211, commonality with other parts, ability to use "any old" NAND Flash reading IC etc.

Any hints.

Background:

A good friend who had been warned about the need for data backup failed to heed the warnings as has "lost access" to an extremely valuable set of files stored on a USB memory stick. She is studying to be a teacher and the files are lesson plans and other material created over a long period of time.

The USB memory stick was physically severely damaged by being knocked sideways while plugged into a USB port. Apparently attempts were made to read it by pushing it together. When it got to me 3 of the 4 connections between PCB and connector were broken. I resoldered these, expecting there to be a good chance of restoring operation.

When plugged into a USB port the memory stick draws a large current (probably port limited) and the controller gets VERY VERY hot - I first discovered this by burning myself badly on the IC. The actual memory IC is on the opposite side of the PCB. It also appears to get hot BUT this may be due to the very large Wattage going into the controller IC. Desoldering will happen.

Part number corrected to 29F32G08QAA

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    \$\begingroup\$ Would the person who downvoted this like to explain why. If you can advise how to ask a question with more adequacy, yet without excess baggage, or how to more clearly state the problem; or if you can explain how this question is not one involving electronic design or construction; then your great erudition, sagacity, perspicacity, wisdom and (who can doubt it) wit, and no doubt immense personal beauty and all round joy de vivre, would without doubt benefit from the increased exposure. No? \$\endgroup\$
    – Russell McMahon ♦
    Commented Nov 21, 2011 at 11:28
  • \$\begingroup\$ Ouch - 6 results on google for a datasheet for the 29F32G080AA ... Not looking good on that front... \$\endgroup\$
    – Majenko
    Commented Nov 21, 2011 at 11:32
  • \$\begingroup\$ The controller does seem to be a popular one though. "This controller is found in the flash drives from different manufacturers, such as: Kingston, Kingmax, A-data, etc." \$\endgroup\$
    – Majenko
    Commented Nov 21, 2011 at 11:35
  • \$\begingroup\$ @Russell - I'm the second downvoter. I downvoted it because it irremediably lacks data which will be needed to answer the question: schematics, the datasheet for the flash module, information about normal behavior. It lacks these because it's a question about debugging consumer electronics. You've made a great effort to provide all the information you can, but you're in a fundamentally different position than the designer of the flash drive would be in if suffering the same troubles. Also, thank you for the compliments! \$\endgroup\$
    – Kevin Vermeer
    Commented Nov 21, 2011 at 15:09
  • \$\begingroup\$ who had been warned about the need for data backup failed to heed... Duh! Looks like she got what she asked for. Duh, again. \$\endgroup\$
    – Olin Lathrop
    Commented Nov 21, 2011 at 16:35

3 Answers 3

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It looks like you can get the datasheet for the flash chip and thereby rig up something to read the bits. However, that may be a long way from recovering the data. Somewhere in the pile of bits is control information private to the flash drive, probably some wear levelling data, and then file system structures as seen by the operating system.

You should be able to get info on the file system (probably FAT32), but the private flash drive structures and how/where it actually stores the data is unlikely to be specified publicly. I think the best bet is to get another flash drive of the exactly the same model, replace your flash chip into that drive, and hope no additional state is stored in non-volatile memory in the controller.

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  • \$\begingroup\$ Ah. That's better. No dead fish or Moon phases either :-). And yes, thanks, that's a pretty fair summary of what I've heard from elsewhere so far. Veronica Merryfield sent me a link to the patent that covers their FTL system - hopefully it's not going to get that hard :-) \$\endgroup\$
    – Russell McMahon ♦
    Commented Nov 21, 2011 at 19:42
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    \$\begingroup\$ @Russell: Actually this whole project is pretty iffy, so may require appropriate waving of dead fish. \$\endgroup\$
    – Olin Lathrop
    Commented Nov 21, 2011 at 21:14
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    \$\begingroup\$ "Pretty iffy" is a 'pretty broad' sobriquet. One can't always choose what reality dishes up - only whether to rise to the challenge or not. I now know what factors are liable to affect the outcome - and that the chances of success are small :-(. I have a USB memory stick that appears to be the same on its way from a local auction site and will know shortly if I am going to be able to attempt a repair. That range of iffy acceptable. I may yet get to fight the Dragon and may even get to succour the fair Damsel. Seems good to me. \$\endgroup\$
    – Russell McMahon ♦
    Commented Nov 22, 2011 at 11:02
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It may be this device:

http://www.micron.com/products/ProductDetails.html?product=products/nand_flash/mass_storage/MT29F32G08ABAAAM73A3WC1

Datasheets seem to be under NDA, but there's also a link to here:

http://onfi.org/specifications/

which has generic specifications.

I don't think this is really the answer to your problem, but you could...

  • Establish enough to wire up the bare NAND chip to a favourite microcontroller (possibly via some level shifters).
  • Then "bit-bang" the interface to download the whole chip over serial. This'll take a while.
  • You may then be able to run strings over that image to extract pure text content.

But there'll be all sorts of error correction and fragmentation getting in the way, so this probably isn't worth the effort.

Desoldering one or other chip and replacing it with a working one, or in a working flash drive of similar ilk is probably your best bet. good luck!

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Olin's suggestion of transplanting the chip into another same model drive is likely fastest if it works and if you have the capability to do the soldering cleanly enough.

A fallback possibility would be to wire the chip up to something with sufficient GPIOs and access it through a software implementation of the data sheet protocol. IIRC, this can just barely be done with a bidirectional parallel port. A serial connected microcontroller (arduino, etc) would also be a possibility - either have it perform the access cycles and stream the data back over the serial at a few hundred kilobaud, or implement a command language for telling it what control signals to assert and get the data back really, really slowly (multiply the really by a few more if it's a USB-serial model, given the added latency). For a one off project slow is of course relative - ie, after you spend a weekend building and debugging it, letting it run over night or even for a few days doesn't seem so bad.

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  • \$\begingroup\$ Yesish :-). New controller onto old PCB is slightly easier soldering (not an issue) and slightly less chance of damaging Flash memory (greater issuie). But old board is walking wounded mechanically so will probably transfer Flash. USB to flash translation is the greatest unknown - Micron use their own patented algorithm and I don't know if dropping an old Flash into a new controller's mapping field is gong to be painless or disastrous or somewhere in between. Then there is Flash wear levelling with mapping table maybe held in old controller (dead) or in old flash (alive, I hope). \$\endgroup\$
    – Russell McMahon ♦
    Commented Nov 23, 2011 at 0:22
  • \$\begingroup\$ I personally would rather desolder and move a nand flash chip with pins on two widely spaced sides than a PQFP with pins on all four sides. And I say that after having had to successfully pull a .5mm 48PQFP off a handmade PCB at home using braid and music wire and put it back down rotated 90 degrees ;-) But I can see why you would rather work on a replacable chip than an irreplaceable one. If the controller transplant doesn't work, consider soldering the wires for software access to the controller's pads. \$\endgroup\$
    – Chris Stratton
    Commented Nov 23, 2011 at 0:25

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